A significant number of older people have an elevation of intraocular pressure (IOP) but only a small portion of this population are susceptible to glaucomatous damage and gradually lose vision. The treatment of glaucoma, aimed at lowering the IOP, cannot be applied to all the subjects with only an elevated IOP. It is therefore of primary importance to develop a test capable of identifying the individuals susceptible to glaucomatous damage. This will allow clinicians to initiate therapy at an early stage and hopefully to prevent of delay a loss of vision. We have postulated that a weakness in the structural support of the optic nervehead can cause susceptibility to damage. We have therefore developed a noninvasive method to measure the optic nervehead compliance (weakness). The method was shown to be safe, reproducible, sensitive, and applicable to humans. In the present research we intend to initiate clinical trials of this new method and to check its relevance to the prediction of glaucomatous damage. We will study the optic nervehead compliance in different stages of glaucoma and compare the values to those of normals and ocular hypertensives. Different factors capable of yielding false-positive results will be studied. The optic nervehead compliance will then be measured in ocular hypertensives. Two groups, one having a very high and one a very low probability of developing loss of vision will be studied and followed with time. This will provide and indication of the predictive value of the optic nervehead compliance measurement. In addition, a group of patients with low IOP and loss of vision (low tension glaucoma) will be studied in order to test if their susceptibility to damage is not associated with a low structural support of the optic nervehead.